"If you pluck someone off the street, whether in New York or Wichita or Seattle or Sacramento, and ask them how many steps people should aim for per day in order to get enough physical activity, they'll probably tell you 10,000. In an age in which pedometers are cheaper, more accurate, and more feature-rich than ever, this number has taken on almost mythical proportions -- a lofty-sounding goal (in reality, it's approximately five miles, and a reasonably active person can pull it off fairly easily) that separates the active-lifestyle haves from the slothful have-nots.

"But is there any medical reason to embrace this number? Not really. That's because the 10,000-steps-a-day recommendation has nothing to do with sedentary, fast-food-drenched circa-2015 America. Rather, the recommendation first popped up in a very different food and environment: 1960s Japan."